Smooth-On Simpact™ 85A - 840gr

Product Description

Simpact™ 85A is a urethane rubber with superior physical properties and performance for creating molds used for casting cement. Vacuum degassing is not required for most applications. Simpact™ 85A offers many advantages, including:

• Reproduces fine details accurately.
• Has a very low shrinkage rate (<0.02mm / mm).
• Provides excellent durability for repeated casting.
• Easy to measure (85A:100B by weight, a scale is required).
• Is highly resistant to cement casting.
• Is easy to use.

Recommended Uses

Simpact™ 85A is used to create flexible molds for cement casting. However, it can also be used to produce objects that are rigid yet still somewhat flexible, such as prop weapons, decorative items, components, etc. Finished molds can be used repeatedly for casting plaster, cement, and ceramic-like mixtures.

Instructions for Use

Simpact™ 85A rubber is a product intended for professionals only. It is important that you read and understand the instructions before use.

KEEP OUT OF REACH OF CHILDREN

Safety – Use the rubber in a well-ventilated area. Wear safety glasses, long sleeves, gloves, and a mask.

Store and use the rubber at room temperature (23°C). Lower or higher temperatures will drastically reduce pot life and cure time. Storing the rubber at lower or higher temperatures will reduce its shelf life, whether the container is opened or sealed. These products have a limited shelf life and should be used as soon as possible.

Applying Release Agent

• Because urethanes act as adhesives, the original model must be well protected. When the model is made of porous material (wood, stone, cement, plaster), it must be sealed thoroughly with SuperSeal™ or another sealer, which must dry completely before applying a release agent such as Universal Mold Release Spray code 9418006). If the model is non-porous (metal, glass, etc.), apply only a release agent such as Universal Mold Release Spray code 9418006.

• If using the rubber as a mold: Applying a release agent to the mold, such as Universal Mold Release Spray code 9418006, before casting cement helps prevent long-term degradation of the mold and makes demolding easier (allow the release agent to dry for 30 minutes before casting).

• If using the rubber as a casting material inside a mold: Apply a release agent to the mold such as Universal Mold Release Spray code 9418006. Apply a thin coat and allow it to dry for 30 minutes. If compatibility between the rubber and the release agent is uncertain, perform a small test first.

Mixing Ratios

The mixing ratio is 85A:100B by weight (a simple scale is sufficient). Incorrect ratios may result in faster or slower curing and may reduce mechanical properties. Do not attempt to add extra catalyst (Part B) to accelerate curing. Curing can be accelerated by applying gentle heat. Note: After the mold cures, it may be heated to 65ºC for 4–8 hours to improve its physical properties and performance.

Mixing Instructions

Liquid urethanes absorb atmospheric moisture. Mixing tools (spatulas, containers, etc.) must be made of metal or plastic, clean and dry. IMPORTANT! Mix Part B thoroughly before combining it with Part A. Mix only the amount needed. Pour both components into a clean container and use the mixing spatula to combine them for about 1 minute, scraping the bottom and sides thoroughly.

Casting Instructions

For best results, begin pouring the rubber at the lowest point of the mold, allowing it to rise slowly and naturally to cover the model. Pouring in a steady, uniform stream minimizes trapped air bubbles. The rubber should cover the model by at least 1 cm above its highest point.

Pot Life / Cure Time

Pot life and cure time vary significantly depending on ambient temperature. Simpact™ 85A must be used at room temperature around 23°C, never below 18°C. For optimal results, the environment should be at least 23°C with relative humidity below 50% RH.

Pot life: 1 minute

Cure time: 2 hours

Transport and Storage

The rubber should be stored in tightly sealed containers during transport and storage. Store at room temperature (23°C), in a shaded, dry area. When stored properly, the rubber has a shelf life of 12 months. Higher temperatures will reduce shelf life, whether the container is opened or sealed. These products have limited shelf life and should be used as soon as possible. Although the rubber may still be usable after a longer period, performance may be reduced. Ensure containers are tightly sealed.

Properties / Characteristics

• Color: Off-white
• Mixing Ratio: 85A:100B (by weight)
• Pot Life: 4 minutes
• Demolding Time: 2 hours
• Viscosity: 1100 mPa·s
• Hardness (Shore A): 85
• Tensile Strength: 10.84 N/mm²
• Tear Strength (Die C): 182 pli
• Elongation at Break: 164%
• Shrinkage: <0.02 mm / mm
• Shelf Life: 12 months
• Can be pigmented using polyurethane resin colorants.

Indicative Hardness Chart:

Disclaimer

These data should not be used as specifications. The values listed are typical and should not be considered minimums or maximums. Our technical advice, whether spoken or written, is given in good faith but carries no warranty, expressed or implied. All products are sold with the understanding that the buyer will perform their own tests to determine product suitability for specific applications and conditions. We assume no responsibility for proper product use, nor for user or property safety—these are solely the user’s responsibility. Any information or suggestions are provided without guarantee of any kind, and buyers are solely responsible for any loss arising from the use of such information or suggestions. Before using any of our products, users must familiarize themselves with the corresponding technical data sheets and safety data sheets we provide.